In a previous (one of many...) life, yes.... LOL

 

I'll to that.

 

Not close enough,
Op, leave the 862 heads on it and give it a try, If it pings which I don't think it will Just put a bigger cam in it with an intake valve close event a few degrees later than the one you have now and you will be good to go

 

this is what i came up with for compression

 

There is always the option with the 317's to send them out for a Stage 1 valve job since they already have bigger valves. You would gain more HP back than you loose due to the compression drop and be plenty safe on pump gas. I'm figuring my 317 stage 1's on a 408 shortblock with 8cc dish pistons is right around 10:1 and should be able to get close to 450rwhp through a 4L80E with a 222/233 Ghost cam + Early truck intake (looks like a rattle can rebuilt LQ4 LoL).